High Efficiency Video Coding (HEVC) is a new-generation video coding standard after H. 264. HEVC still uses a hybrid coding framework of H.264, such as intra-frame prediction and inter-frame prediction, residual two-dimensional transform, loop filtering, and entropy coding. However, in this hybrid coding framework, a lot of technology innovations are further made in HEVC, where typical innovative technologies include:
(1) a quadtree based splitting structure, where a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU), and a transform unit (TU) are used to describe an entire coding process. The CTU is a maximum coding unit in HEVC; the CTU may be subsplit into CUs, where the CUs are similar to macroblocks or sub-macroblocks in H.264, and each CU is a 2N×2N pixel block (N is a power of 2); and pixel block sizes of the PU and TU are 4×4;
(2) up to 35 intra-frame prediction modes included in an HEVC test model (EM);
(3) an advanced motion estimation technology, such as an advanced motion vector prediction (AMVP) technology and a motion merge technology;
(4) an adaptive loop filter technology, for example, using a sample adaptive offset (SAO) filter; and
(5) a semantic-based entropy coding technology, for example, an entropy coding technology using adaptive binary arithmetic coding (CABAC).
In comparison with H.264, HEVC has the foregoing innovative technologies. Therefore, in comparison with using H.264 for coding, using HEVC for coding may achieve double compression efficiency, that is, in a case in which same video picture quality is ensured, a bit rate of a video stream is reduced by 50%.
While improving coding efficiency, HEVC also inevitably increases coding complexity. A feasible manner for reducing HEVC coding complexity is to optimize an inter-frame predictive coding process in HEVC. However, currently only a single optimization manner of inter-frame predictive coding is available, and it is necessary to find more optimization manners.